Contamination of drinking water by lead, copper, and other metals, as well as by biological and other contaminants, can pose significant health risks in many cases, especially if lead or copper pipes or fittings, or any other contaminant sources, are present in the plumbing system of a home or other building. Lead can enter drinking water when service pipes that contain lead corrode, for example when the water has high acidity or high alkalinity that corrodes pipes and fixtures. The most common problem is with brass or chrome-plated brass faucets and fixtures, and with lead solder, from which significant amounts of lead can enter into the water. Even though these materials have been largely banned from use in new construction, some homes, especially older homes, may still have significant amounts of lead in their plumbing systems. Often, such contaminants are present only in the plumbing of the building itself.
In such cases, if water is allowed to stand within an indoor plumbing system for longer than a minimum “build-up period,” which is typically several hours but can be more or less, lead and other contaminants can slowly leech into the water, such that the contaminants are ingested upon the next use of a drinking water tap. Similarly, biological contaminants that are largely suppressed due to low temperatures in exterior, primary water supply systems can multiply and increase in concentration when water is allowed to stand and to rise to warmer temperatures within the plumbing system of a home or other building.
Lead, in particular, can pose a significant health risk to a person if too much of it enters the person's body. Lead builds up in the body over many years, and can cause damage to the brain, red blood cells, and kidneys.
Lead in drinking water can be a special problem for pregnant women, and for infants, whose diets may be mostly liquids, such as baby formulas or concentrated juices mixed with water. Smaller bodies can absorb lead more rapidly than bigger ones, so amounts of lead that would not hurt an adult can be very harmful to a child. A child's mental and physical growth can be permanently harmed by too much lead.
Lead is rarely found in natural sources of water such as rivers and lakes or underground aquifers. Nor are lead and other contaminants typically found in the water distribution systems that distribute water from a primary source to individual homes and other buildings. Instead, drinking water is most often contaminated due to corrosion of pipes and fittings and growth of biological organisms while the water is standing in pipes that lead from the primary source to the consumer, for example through a local distribution system or within a home or other building, waiting to be dispensed and consumed.
It should be noted that, while some parts of the present disclosure recite contamination by lead of pluming in a house or home, the present disclosure also applies to contamination by other metals and substances, including biological substances that may tend to breed in standing water that is within a plumbing system of a building, or of any other secondary water distribution system, but be relatively absent from primary distribution lines.
When lead or another toxic substance is found in the drinking water of a home or other building or distribution system, the resident or other owner faces a difficult decision regarding whether to commence an expensive project to replace the plumbing system, or to install expensive, high maintenance filters.
Another approach to mitigate the threat of contaminants from drinking water within a building is to flush taps before they are used to dispense drinking water, so that any water that may have become contaminated while standing within the plumbing system is replaced by freshly delivered water that can be assumed to be free of contaminants. However, this approach requires patience and discipline on the part of the user, and is therefore subject to human error. Also, considerable amounts of water can be wasted due to such decontamination flushing. For example, if the water is allowed to flush from a tap until a noticeable drop in temperature is felt, this will result in purging not only of the water within the building, but also the water within the exterior distribution pipes that deliver water from a primary source to the building. These exterior distribution pipes are typically free of contaminants, but are often close enough to the terrain surface to contain tepid water that is similar in temperature to the water within the building. As a result, both time and water are wasted.
Purging of contaminants can be automated by devices that flush a tap on a timed basis, whereby the tap is automatically flushed for a specified flushing duration, and the flushing is repeated periodically according to a maximum “build-up” time that is determined to be “safe.” Automated flushing can provide clean water to a user on demand, eliminating the need for user discipline and patience. However, these automated approaches can greatly increase the amount of water that is wasted, by flushing a tap even when it is not being used, and by flushing more water than necessary each time the tap is purged of contaminants.
Flushing can also be used to eliminate contaminants that are temporarily introduced into a water source due to a repair or other temporary cause. For example, a repair made at a primary water source may introduce or stir up sediments that increase water turbidity, or a workman may add a dose of chlorine to the water after performing a repair, so as to eliminate any biological contamination that may have been introduced. These contaminates will typically remain until they are cleared out of the system through normal water use and/or flushing.
What is needed, therefore, is an apparatus and method for reducing ingestion by a user from a water tap of contaminants in a plumbing system, without replacement of the plumbing system, without need for expensive filtration systems, and with minimum waste of water.